This Bus-Size Whale Is Even More Unusual Than We Thought

Scientists are starting to piece together the secret life of the little-seen Omura's whale, which has a peculiar diet.

3 Minute Read

By Traci Watson

PUBLISHED February 10, 2016

Well after its discovery a decade ago, the sleek swimmer called the Omura's whale remained an enigma. Reports of live animals were vague and unconvincing, leaving the whale's habits and even its markings a mystery.

Now, scientists are starting to piece together the secret life of the little-seen species.

“People see our photos and videos and say, ‘What are they feeding on? I don’t see anything there,’” says Salvatore Cerchio, a marine mammal biologist at the New England Aquarium and leader of the first team to document the whales’ lives.

Sea surveys are costly, says Kershaw, who wasn't involved in the new study. And the Omura’s keeps a relatively low profile compared to showboatslike humpbacks, which make eye-catching leaps out of the water.

Even after it was unmasked in the scientific literature, the Omura’s was still known only from dead specimens, some hauled onto whaling ships, others stranded on coastlines.

Then came the Omura’s big moment.

Scouting for dolphins near Madagascar a few years ago, Cerchio spotted some medium-size whales. After the DNA analysis came back, on December 24, 2014, Cerchio learned he’d stumbled onto Omura’s whales—“a very nice Christmas gift,” says Cerchio, a National Geographic explorer.

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An Omura's whale surfaces off Nosy Be, Madagascar, showing part of its "dramatic and beautiful" white pattern.

Cerchio’s team made 44 sightings of the whales off Madagascar during 2013 and 2014 and more than 80 sightings in 2015.

"Very Thin Soup"

The team’s first round of data, published in October 2015 in the journal Royal Society Open Science, suggest that these Omura’s at least are homebodies. The sightings also suggest the Omura's sticks to tropical and subtropical waters.

The tropics, on the other hand, provide slim pickings for baleen whales like Omura's, which filter small organisms through their mouths.

"We call it the very thin soup,” says marine-mammal biologist Matt Leslie of the Scripps Institution of Oceanography, who wasn't part of the new study. So “one of the big questions is how they make their living.”

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Cerchio’s team, which observed the whales swallowing murky water as recently as late 2015, suspects the whales are filtering out food such as fish eggs or tiny plankton that are almost invisible to the human eye.

Edge of the Iceberg

The new observations also showed the Omura’s social habits are distinctive. It doesn’t form tight-knit pods like many other whale species, but it isn’t solitary either.

Instead the Omura’s was seen hanging out in loose groups of up to a half-dozen animals. Animals stay within hearing range of each other, but give each other plenty of personal space.